The Living World: Hot Deserts Flashcards
Characteristics of HOT DESERTS
- Roughly 30 degrees north and south of the equator
- Cover 1/5 of the world’s surface
- Sinking air stops prevents clouds from forming
- This causes high daytime temps, low nighttime temps and low rainfall
- Plants and animals have to be well adapted to survive in these conditions
What are desert soils like?
- Sandy, stony with little organic matter due to lack of leafy vegetation
- Dry but can soak up water rapidly after rainfall
- Evaporation draws salts to the surface, often leaving white powder on ground
- NOT very fertile
How are plants adapted?
E.g. cactus
- thin, spiky or glossy leaves (avoid water loss)
- deep roots (to tap underground water)
- thick, waxy skin (avoid water loss, reflect heat)
- spikes (protects from animals)
- lies dormant for years until rain falls
E.g. cactus
How are animals adapted?
E.g. camels
- long eye lashes, hairy ears, closing nostrils (keep sand out)
- thick eyebrows (shade eyes from sun)
- wide feet (don’t sink in sand)
- store fat in humps (can go months without food)
- body temp. can change (avoid water loss through sweating)
- thick fur (warm at night)
- leathery knees (can kneel in hot sand)
How is human activity and climate change threatening the biodiversity?
- development and high pop. contaminate water supplies
- drier weather means animals migrate to cooler areas
- some don’t have anywhere to go, leading to extinction
Plants in the desert: SUCCULENCE
- store water in fleshy leaves, stems or roots
- can quickly absorb large amounts of water through widespread, shallow roots and can store this water for long period of time
- metabolism slows during drought so stomata stays closed, water loss almost stops
Plants in the desert: DROUGHT TOLERANCE
- photosynthesise with low leaf moisture level
- shed leaves to prevent water loss through transpiration
- become dormant during drought
- deep roots penetrate soil and rock to tap underground water
Plants in the desert: DROUGHT AVOIDANCE
- annuals (survive one season, have rapid life cycle, then die after seeding)
- seeds last for years and germinate when soil moisture is high
- some germinate in autumn after rain and before winter cold sets in, seedlings survive winter frost and flower in spring
Desertification
Process in which land becomes dry and degraded as a result of climate change or human activities or both
Opportunities in the Thar Desert: SUBSISTENCE FARMING
- although a good deal of farming in the desert is subsistence farming, some crops are sold at local markets
- hunter-gatherers survived in desert by hunting animals and gathering fruit and natural products (Khali’s tribe), most basic form of subsistence farming
•climate presents huge challenge: unreliable rain, frequent droughts
Opportunities in the Thar Desert: IRRIGATION AND COMMERCIAL FARMING
- main form is Indira Ghandi Canal, total length of 650km
- canal provides drinking water to many people in desert
- commercial farming in form of crops now flourishes in area that used to be scrub desert
•mainly benefits cities on Jodhpur and Jaisalmer
Opportunities in the Thar Desert: MINING AND INDUSTRY
- Rajasthan is rich in various minerals and valuable reserves of stone:
- at Jaisalmer, Sanu limestone is main source of limestone for India’s steel industry
- valuable reserves of rock marble quarried near Jodhpur for construction industry
•Quarrying could effect landscape, bad for tourism
Opportunities in the Thar Desert: TOURISM
- has beautiful landscapes, popular tourist destination
- In Jaisalmer, desert safaris on camels is popular
- local people benefit from being guides and looking after camels
- Thar Desert national park protects rare wildlife that has adapted
Opportunities in the Thar Desert: SOLAR ENERGY
- plenty of solar radiation
- lots of barren land to put down solar panels on to make lots of energy for energy companies and the country
•expensive for locals to pay for farmland and solar panels
Salinisation
The deposition of toxic salts on the ground surface following the evaporation of water
